The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventor, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Glaucoma is a neurodegenerative disease of the optic nerve leading to irreversible blindness. In simple terms, it is defined by loss of nerve fibers in the optic nerve, diagnosed by observation of neuroretinal rim loss in the optic nerve head (ONH) (FIG. 1A). Early detection and treatment of glaucoma can slow down the disease progression and prevent significant visual impairment. Detection of early glaucoma is best achieved by evaluating the retinal nerve fiber layer (rNFL) by optical coherence tomography (OCT). OCT analysis of the rNFL in essence measures the thickness of the nerve bundles that make up the optic nerve prior to entering the optic nerve, while emerging from the retina. The current measurement is made by evaluating the thickness of the rNFL 3.6 mm around the center of the optic nerve head (ONH) (as shown in a circle in FIG. 1B). However, the rNFL around the optic nerve head is complex, and measurement of the area 3.6 mm from the center of the ONH is merely a sample of the nerve bundles.
There are other eye diseases, in addition to glaucoma, that affect the nerve fiber bundles, including optic neuropathy, papilledema, optic neuritis and multiple sclerosis (MS), and idiopathic intracranial hypertension (IIH). It is desirable to have more accurate techniques for measuring each of these conditions, as well as others related to changes in never fiber bundle.